Cher (left) and songwriter Diane Warren in 2010.Photo:Kevin Winter/Getty

Cher (L) and songwriter Diane Warren arrive at the premiere of Screen Gems' “Burlesque” at Grauman�s Chinese Theater on November 15, 2010 in Los Angeles, California.

Kevin Winter/Getty

Cherhas plenty to say about her longtime friend, songwriterDiane Warren.In an interview for the new documentaryDiane Warren: Relentless, which premiered in theaters on Jan. 10 and will be available for streaming on MasterClass starting Jan. 23, Cher, 78, offers the first words that come to mind when thinking about Warren, 68.“How about that Diane is nuts, can we start off with that? I don’t think she would argue with me for a second,” Cher says. “Nuts, cheap, unrelenting, optimistic, sweet. She’s just crazy — oh my God. But she writes great songs.”‘Diane Warren: Relentless’.Courtesy of MasterClassSpeaking to PEOPLE about the documentary, Warren says she disagrees with some of the adjectives Cher uses to describe her. “I don’t know why she calls me [cheap],” she says. “It’s not really cheap — I was never cheap. I paid for ‘If I Could Turn Back Time.’ “The song, one of Cher’s most iconic hits, wasn’t an easy sell. “I go up to her and I go, ‘Cher, you have to do the song,’ [She goes] ‘I f—– hate it, I f—— hate it,’ ” Warren says of trying to get Cher to record it. “I grabbed her legs. I held her feet to the ground literally, and I go, ‘Until you say you’re going to at least try it….’ ”Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.Cher, however, was resolute in her refusal. “I kept saying, ‘No, I do not want to record this song. I don’t want to do it. I hate it,’ ” she recalls in the documentary.It wasn’t until Warren offered to cover the cost of the track and promised to release her grip on Cher’s legs that the singer finally agreed to give it a try. “I thought she’s the cheapest chick I know,” Cher says with a laugh. “But from the moment I started to sing it, it was perfect. I did it in like 15 minutes.”Warren recalls watching from the booth as Cher began to sing: “I remember looking in the glass booth, I see her singing, and she looked at me like, ‘You f—ing b—-, you were right.’ ”Looking back on the battle to get the song recorded, Cher reflects, “I mean, Diane is unrelenting. She’s unrelenting, but thank God, because it’s one of my favorite songs, and it’s one of my biggest hits.”Cher (left) and Diane Warren as Warren receives her honorary Oscar in 2022.Valerie Macon/AFP/GettyThe two have remained close friends since the release of “If I Could Turn Back Time” in 1989, and their bond has only grown stronger. Cher presented Warren with herhonorary Oscarin 2022, making her the first songwriter in history to receive one. “I haven’t gotten the competitive one yet,” the 15-time nominee jokes to PEOPLE.Seriously, though, Warren is still hoping for that non-honorary Oscar, and she could be in the running to be nominated for a 16th time this year for her song “The Journey,” which appears inThe Six Triple Eight. “It would be cool to win. I never did have a sweet sixteen,” she jokes.Still, her greatest prize is getting to do what she loves.“There’s so many wins with it, really,” says the woman whose songwriting hits includeCeline Dion’s “Because You Loved Me” andAerosmith’s “I Don’t Want to Miss a Thing.” “You get to write something that makes somebody feel good or makes them feel less alone or something, or it just moves them. But the main thing is I get to write songs that I love.”Diane Warren: Relentlessis now playing in theaters and will be available to stream on MasterClass starting Jan. 23.

Cherhas plenty to say about her longtime friend, songwriterDiane Warren.

In an interview for the new documentaryDiane Warren: Relentless, which premiered in theaters on Jan. 10 and will be available for streaming on MasterClass starting Jan. 23, Cher, 78, offers the first words that come to mind when thinking about Warren, 68.

“How about that Diane is nuts, can we start off with that? I don’t think she would argue with me for a second,” Cher says. “Nuts, cheap, unrelenting, optimistic, sweet. She’s just crazy — oh my God. But she writes great songs.”

‘Diane Warren: Relentless’.Courtesy of MasterClass

Diane Warren: Relentless streaming on MasterClass

Courtesy of MasterClass

Speaking to PEOPLE about the documentary, Warren says she disagrees with some of the adjectives Cher uses to describe her. “I don’t know why she calls me [cheap],” she says. “It’s not really cheap — I was never cheap. I paid for ‘If I Could Turn Back Time.’ "

The song, one of Cher’s most iconic hits, wasn’t an easy sell. “I go up to her and I go, ‘Cher, you have to do the song,’ [She goes] ‘I f—– hate it, I f—— hate it,’ ” Warren says of trying to get Cher to record it. “I grabbed her legs. I held her feet to the ground literally, and I go, ‘Until you say you’re going to at least try it….’ ”

Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

Cher, however, was resolute in her refusal. “I kept saying, ‘No, I do not want to record this song. I don’t want to do it. I hate it,’ ” she recalls in the documentary.

It wasn’t until Warren offered to cover the cost of the track and promised to release her grip on Cher’s legs that the singer finally agreed to give it a try. “I thought she’s the cheapest chick I know,” Cher says with a laugh. “But from the moment I started to sing it, it was perfect. I did it in like 15 minutes.”

Warren recalls watching from the booth as Cher began to sing: “I remember looking in the glass booth, I see her singing, and she looked at me like, ‘You f—ing b—-, you were right.’ ”

Looking back on the battle to get the song recorded, Cher reflects, “I mean, Diane is unrelenting. She’s unrelenting, but thank God, because it’s one of my favorite songs, and it’s one of my biggest hits.”

Cher (left) and Diane Warren as Warren receives her honorary Oscar in 2022.Valerie Macon/AFP/Getty

US songwriter Diane Warren holds up her honorary Oscar next to singer-actress Cher, during the Academy of Motion Picture Arts and Sciences' 13th Annual Governors Awards at the Fairmont Century Plaza in Los Angeles on November 19, 2022.

Valerie Macon/AFP/Getty

The two have remained close friends since the release of “If I Could Turn Back Time” in 1989, and their bond has only grown stronger. Cher presented Warren with herhonorary Oscarin 2022, making her the first songwriter in history to receive one. “I haven’t gotten the competitive one yet,” the 15-time nominee jokes to PEOPLE.

Seriously, though, Warren is still hoping for that non-honorary Oscar, and she could be in the running to be nominated for a 16th time this year for her song “The Journey,” which appears inThe Six Triple Eight. “It would be cool to win. I never did have a sweet sixteen,” she jokes.

Still, her greatest prize is getting to do what she loves.

“There’s so many wins with it, really,” says the woman whose songwriting hits includeCeline Dion’s “Because You Loved Me” andAerosmith’s “I Don’t Want to Miss a Thing.” “You get to write something that makes somebody feel good or makes them feel less alone or something, or it just moves them. But the main thing is I get to write songs that I love.”

Diane Warren: Relentlessis now playing in theaters and will be available to stream on MasterClass starting Jan. 23.

source: people.com